Abstracts

Rationale: The use of vigabatrin, an effective anti-seizure medication for treatment of infantile spasms and focal seizures in tuberous sclerosis (Bombardieri R, 2010; Camposano SE, 2008; Chu-Shore CJ, 2010; Curatolo P, 2006; Friedman D, 2013; Greiner HM, 2012), is presently limited by fear of often irreversible peripheral vision loss that can occur following its use (Camposano SE, 2008; Eke T, 1997; Westall CA, 2014). One current hypothesis holds that this vision loss results from vigabatrin decreasing blood taurine levels, as taurine deficiency has been shown to cause retinopathy in several species (Heim MK, 2012; Jammoul F, 2009; Froger N, 2014), and taurine supplementation may rescue retinopathy models (Froger N, 2010; Jammoul F, 2010). A “white paper” presently recommends that taurine levels should be checked, and supplementation considered (Krueger DA, 2013), based on a small amount of existing data suggesting that patients on vigabatrin may have lower taurine levels (Jammoul F, 2009). However, data are lacking to evaluate the natural history of taurine levels in pediatric patients, and in particular the effect of vigabatrin on taurine.Methods: Here, we retrospectively characterize taurine levels in a population of pediatric patients. We searched the Stanford STRIDE database for all children <18 years of age who had taurine levels checked during 2006-2015. There were three groups of children studied: 1) children not taking anti-seizure medications (n=556), 2) children taking anti-seizure medications but not vigabitrin (n=433), and 3) children taking vigabitrin (n=16).Results: Plasma taurine levels for children taking vigabatrin were not significantly lower than the other groups. In fact, taurine levels in children on vigabatrin fell about in the middle of levels seen on various anti-seizure drugs. Using data from children not on any anti-seizure medications, we found that plasma taurine levels decrease during early life (most prominently in the first year), as do CSF taurine levels. Plasma taurine levels did not, however, correlate with vigabatrin dose or time on vigabatrin.Conclusions: Given these data, further prospective studies are needed to reveal whether taurine levels are relevant to vigabatrin-associated visual field loss.